A rotary disc valve for inflating and deflating pressure cells in a therapeutic sleeve is disclosed in U.S. Pat. No. 6,779,557, incorporated herein by reference. This rotary disc valve comprises a stator with a plurality of fluid flow ports and a rotary distributor with a plurality of channels arranged in a channel pattern. The channels are adapted to connect the ports between them and/or to the environment in a plurality of predetermined combinations, each combination being associated with an angular position of the rotary distributor with respect to the stator. The succession of combinations performed during a full or partial unidirectional turn of the rotary distributor constitute a predetermined sequence. The rotary distributor comprises a rotor and a mask mounted movably thereon, the rotor and the mask accommodating the plurality of channels. The mask is adapted to change the channel pattern by changing its position with respect to the rotor, thereby enabling the rotary disc valve to perform different predetermined sequences corresponding to different positions of the mask.
JP 01145474 discloses a rotary disc valve with a similar function where the stator comprises two discs fixed with respect to each other, the stator discs slidingly contacting a rotor distributor disc disposed therebetween. The rotor disc has U-channels and through holes connecting the ports of the stator in various combinations during one turn of the rotor distributor disc.
U.S. Pat. No. 4,614,205 discloses a multiport rotary disc valve with a similar function of simultaneous interconnection of a plurality of conduits in accordance with a predetermined cycle. The stator and the rotary distributor in this rotary valve are assemblies each comprised of two parallel plates or discs. The rotary assembly is sandwiched between two parallel plates of the stator assembly. Crossover pipes extend between the rotor plates to form either U-channels or through-passages similar to the above-cited designs.